Two-speed shift on demand auger drive

ABSTRACT

A hydraulic auger system having a hydraulic motor capable of two speed operation, the motor including an output shaft which may rotate and a connected auger. A pressure sensitive kick down valve unit is connected to the hydraulic motor, whereby the unit determines the speed state of said hydraulic motor, based on resistance to rotation of auger, auger speed, or sensed hydraulic pressure.

RELATED CASES

[0001] This application is based on provisional application No. 60/059,374 filed on Sep. 19, 1998.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to construction equipment attachments, and, more particularly, to a new two-speed, shift-on-demand auger drive for drilling holes in the ground.

[0004] 2. Description of the Related Art

[0005] Current auger drives, such as attached to booms, tractors, skid steers and the like, are used to drill holes and telephone post holes, by means of a hydraulic motor attached to an auger.

[0006] Currently in the art there are two-speed drive units, which are manually shifted from between a low speed and a high speed while the hydraulic unit is turning. This function is called shift-on-the-fly.

[0007] Such hydraulic motor is shifted by a signal line controlled by the operator. Typical usage of such a unit, is to start drilling at a high torque level and leave it at such speed until the auguring function is completed. Then, the operator shifts the device to high speed to spin dirt from the auger.

[0008] What is needed in the art is a auguring drive system that may automatically shift between low and high speed drive, thereby have greater throughput.

SUMMARY OF THE INVENTION

[0009] According to the present invention a hydraulic motor is provided, having a single inlet and single outlet for hydraulic power, which utilizes a pressure sensitive kick down valve to shift the hydraulic motor from one speed to another upon sensing a certain degree of pressure from the auguring function. The hydraulic motor is attached between a member such as a boom or frame of vehicle for easy transport, and the output end includes connection to an auger bit. Additionally, the two speed drive may operate in both the forward and reverse operating directions.

[0010] An advantage of the present invention is that the pressure sensitive kick down valve utilized within the system, automatically senses the certain degree of pressure from the auguring rotating function. If the ground conditions are easily augured, the unit may not shift into the high torque mode, since it is not required. If drilling conditions require higher torque than the state the unit currently is, the unit will sense this through the hydraulic back pressure of the system and selectively operate the hydraulic motor in a higher torque mode. Such operation may also operate in the reverse rotating direction by means of a shuttle valve.

[0011] Another advantage of the present invention is that the system will determine automatically if higher torque is needed. Production and throughput levels will increase simply because most ground conditions do not require high torque at all times while auguring.

[0012] A further advantage of the invention is that, compared to known two-speed hydraulic auger systems, no additional plumbing is necessary to connect on operator speed select line.

[0013] Yet another advantage of the present invention, is that it may easily be fitted to any existing utility/construction equipment that has adequate hydraulic pressure to operate the unit. No extensive plumbing or retrofitting is necessary for connecting the invention to the old transportation structure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:

[0015]FIG. 1 is a side view of the present invention; and

[0016]FIG. 2 is a schematic view of one form of the present invention.

[0017] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one preferred embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

[0018] Referring now to FIG. 1, the present invention of the two-speed shift-on-demand auger drive system 10 is shown connected to a member 12, such as a boom or extension member of a utility or construction vehicle. Such vehicle normally provides a source of hydraulic pressure as by an auxiliary hydraulic system. As shown in FIG. 1, such vehicle would be equipped with a hydraulic supply line 14, for supplying sufficient hydraulic power to the hydraulic auger drive system 10. Also connected to boom 12 is a hydraulic fluid return line 16, supplying the previously utilized hydraulic fluid back to the auxiliary hydraulic system. The hydraulic two-speed shift on demand system 10 utilizes a hydraulic motor 20 connected to the hydraulic supply line 14 and hydraulic fluid return line 16. Motor 20 is connected by a swivel or gimbled mount to boom 12 such that in normal operations the output shaft of motor 20 is oriented perpendicular to ground level 24.

[0019] One example of motor 20 is that of a commercially available model, such as a model 51 two-speed hydraulic motor from Commercial Intertech, although others may be equivalently utilized. An auger bit 26 is attached to the output shaft 28 of motor 20.

[0020] The design of the above referenced motor and equivalent other types are such that, motor 20 may be operated at two speeds, one speed for relatively high speed with low torque, and the other speed, that of a relatively low speed with high torque characteristics.

[0021] The present invention includes the use of a pressure sensitive kick down valve unit 30, made from a combination of a motor speed change valve, normally sold with the above referenced motor 20, and connected to the hydraulic supply line 14, along with a hydraulic pressure sensor utilized to measure the hydraulic pressure within system 10.

[0022] In one form of the invention, pressure sensor unit 30 may directly or indirectly measure the pressure of input hydraulic supply line 14. One type of pressure sensor utilized is that of a Hydra-Force KF10-30 kick down sequential interval pilot sensor, which may be connected to the motor speed change valve.

[0023]FIG. 2 shows a schematic of one form of the present invention in which hydraulic oil may enter or exit via lines 14 and 16 through ports 38 and 39. The entry port is switched for forward and reverse, motor rotation. Both ports 18 and 19 are connected by hoses 40 and 41 through a shuttle valve 51. Shuttle valve 51 allows oil from port 38 and 39 with the highest pressure to enter the sensing chamber of the pressure sensing valve 45. Shuttle valve 51 simultaneously blocks any flow to or from port 18 or 19 with the lower pressure.

[0024] When the oil pressure in the sensing chamber of the pressure sensing valve 45 reaches a preset level (the factory level may be set at approximately 1500 psi), the pressure sensing valve 45 opens indicated port 1 to port 2 and the hydraulic oil is allowed to flow through hose 43 to a control port 20 with a motor shifting valve which changes the motor internal oil flow pattern to the high-torque/slow-speed configuration.

[0025] When the pressure in the pressure sensing valve 45 falls below a second preset level (factory level set at approximately 150 psi), the oil flowing through the pressure sensing valve 45 from port 1 to port 2 is shut off and port 2 is connected to port 3. This permits a return spring in the motor shifting valve to move the valve spool back to the low-torque/high-speed position. Oil which is displaced when the valve spool returns, passes through pressure sensing valve 45 from port 2 to port 3 and thereon and into case drain system of motor 20. Port 3 on pressure sensing valve 45 is connected by a line 46 to the case drain system port 48 on motor 20.

[0026] In operation, the pressure sensor unit 30 may be set to actuate the motor speed change valve at a preset level, such as 250 PSI, or any other selected pressure. As long as the hydraulic pressure stays below such preset level the motor will operate in the high speed level. If on a drilling condition where the hydraulic pressure rises, such pressure sensor unit 30 will determine that a higher hydraulic pressure is being applied, therefore a higher torque is needed to auger. At such time, pressure sensor unit 30 will switch motor 20 to drill in a higher torque, low speed state.

[0027] System 10 thereby automatically determines whether or not high torque auguring is necessary. In most applications, hydraulic system 10 will attempt to maintain motor 20 in the high speed, low torque state. With such functionality, drilling and auguring throughput will increase due to the higher average speed.

[0028] Because of the connection to the auxiliary hydraulic system of the attached vehicle, with only supply line 14 and return line 16, the hydraulic system 10 for the present invention may be easily retrofitted to old equipment.

[0029] While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims. 

What is claimed is:
 1. A hydraulic auger system comprising: a hydraulic motor capable of two speed operation, the motor including an output shaft which may rotate; an auger connected to said output shaft; and a pressure sensitive kick down valve unit connected to said hydraulic motor, whereby said unit determines the speed state of said hydraulic motor, based on resistance to rotation of said auger.
 2. The hydraulic auger system of claim 1 further comprising a means for permitting two speed operation in either direction of rotation of said output shaft. 